420811978 has 4 divisors (see below), whose sum is σ = 631217970. Its totient is φ = 210405988.

The previous prime is 420811973. The next prime is 420811991. The reversal of 420811978 is 879118024.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 348680929 + 72131049 = 18673^2 + 8493^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 420811978.

It is not an unprimeable number, because it can be changed into a prime (420811973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105202993 + ... + 105202996.

Almost surely, 2^420811978 is an apocalyptic number.

420811978 is a deficient number, since it is larger than the sum of its proper divisors (210405992).

420811978 is a wasteful number, since it uses less digits than its factorization.

420811978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210405991.

The product of its (nonzero) digits is 32256, while the sum is 40.

The square root of 420811978 is about 20513.7022012118. The cubic root of 420811978 is about 749.3695311977.

The spelling of 420811978 in words is "four hundred twenty million, eight hundred eleven thousand, nine hundred seventy-eight".